The Next Dimension: Road Planning with 3D Technology

Investing in 3D modelling software can reward road projects with improvements to efficiency and safety. Chris Lo talks to infrastructure company URS / Scott Wilson about the use of 3D technology on the complex A46 upgrade project in the UK.

The benefits of 3D modelling for detailed design work are rapidly becoming apparent in all corners of the infrastructure and construction sectors. Though traditionalists might lament the inevitable decline of paper-based schematics and drawings, the advantages of embracing the digital world are impossible to ignore.

Taking the extra time and investing the extra resources to create a 3D model can reap dividends for road upgrade and construction projects, especially large schemes that require a great deal of coordination between contractors, design teams and inspectors.

International infrastructure company URS / Scott Wilson made use of 3D design software for a major upgrade project in the UK. The 28km stretch of the A46 linking Newark and Widmerpool is well-noted for its poor safety record and for operating above its capacity. It is the final section of the road to be upgraded to dual carriageway, at a cost of $572m. The project, which is still ongoing and due for completion in mid 2012, is a massive undertaking involving close collaboration with main contractor Balfour Beatty.

We talked to URS / Scott Wilson's associate for roads, Ian Wildgoose, who was intimately involved in the scheme's design, about using 3D modelling and specialised design software to help economise the project and convince the public that the disruption would be worth it.

"The benefits of 3D modelling for detailed design work are rapidly becoming apparent."

CL: Was the main reason for the upgrade that the section of the A46 was operating way above capacity?

IW: It was, yes. It's the Fosse Way in fact – it's a single track road and very dangerous; because it's a Roman road it follows the natural ground contours, so there are lots of hidden dips, lots of crossroads and junctions with quite a poor safety record, historically. So yes, it was getting way beyond its capacity.

For the A46, all the way from the M1 to Newark, this is the last bit that had not been converted to dual carriageway. The remainder to the south of the scheme is all dual carriageway, and then you hit this single track. It's the missing link in the continuous dual carriageway between the M1 and Newark.

CL: What software has been, or is being, used on the project?

IW: From a geometrical point of view, MXRoad is the central platform that we work with. We design in MXRoad, then we use that basis to convert into computer-aided design (CAD), which is used for all the other drawings. So you've got a basic layout embedded within your CAD drawings that is derived from MXRoad.

CL: What are the project's main challenges, and what is the role of software in overcoming them?

IW: The benefit we had this time was that we, from the outset, knew that the contractor was going to be using GPS-guided earthworks machines. What is traditionally given to the contractor is a big book of numbers, for want of a better expression. We were able to present him with digital files that he was able to almost seamlessly download to Trimble and Topcon software, the surveying software that is part of the machinery. So you've then got a way of providing the design straight from design to bulldozer.

"Because the A46 is a Roman road, it follows the natural ground contours, so there are lots of hidden dips."

The advantages that come with it are quite numerous. You don't have to have any surveyors around the site, so you take away a health and safety risk there; you don't have to have the surveyors going back in when the machines have knocked all the pegs and stakes out; you don't need close attendance with someone who is checking profiles and production. So what you're creating is a safer environment, because you're not mixing people and machines. That's a huge plus.

The other thing we're able to do with it, because inevitably you get varying ground conditions, is relay information immediately back to the design office as the scheme progresses.

We can then adjust landscaping features to accommodate or lose the lesser-quality material at the point of excavation. So as the scheme goes along, you're able to address your earthworks balance in a very close iterative process. It doesn't work quite as well as I'm making it out, but it certainly has been useful.

CL: How did you approach the task of creating a 3D model for the project, and how has it benefited the scheme's execution?

IW: Going back, we decided on the building of a 3D model sometime before the contract. We saw it as a good aid to get the message across to the general public, so we created the model for public exhibitions, going right back to 2006, and developed it to an extent where at the public inquiry in 2007, we had a reasonable-looking 'drive through' that was constantly on a loop in part of the public exhibition.

If there was one particular member of the public who said, "I live here; can you please let me see what the road will look like from my house," we had the ability to then quickly generate a synthetic view from their property. The landscaping was enhanced, such that it was at about 15 years' growth, in the model. We weren't giving them the raw, as-constructed brand new pictures; it's when the landscape had taken hold and provided the mitigation that was planned as part of the works.

CL: So the 3D model played a major role in convincing the public of the benefits of the project?

IW: I think we can safely say that it was possibly the single most convincing piece of evidence for the public. It was very well received, and people, I think, were quite astonished. Of course, members of the public aren't familiar with looking at 2D paper drawings to try to envisage the scheme. Even though some of the exhibition material was quite nicely presented; we did the scheme on aerial photographs and embedded the scheme on it. That gives it a little more life, rather than a cold, 2D piece of paper with a few squiggles on that to many people don't mean anything. We've got the aerial photographs that look quite good, and then looking at a big plasma screen with a helicopter fly through really brought it to life for some people.

CL: Do you think the initial investment of having a more detailed design stage with 3D modelling pays off later by minimising delays and inefficiencies?

"We saw the 3D model as a good aid to get the message across to the general public."

IW: That's difficult to evaluate, but my gut feeling is yes. It's very subjective – you can never envisage what people might have come back to you with had they not seen the 3D model.

From the comments we got, I'm sure there would have been a lot more people writing in and taking up the Highways Agency's time and our time in responding to letters to describe some of the stuff that was blatantly evident on the 3D views.

CL: Based on your experience, what do you think software will be able to achieve in the next five to ten years?

IW: I would hope that we will be designing wholly in a 3D environment, because it lends itself well to being able to test inter-disciplinary design features; making sure that you've not got a water main that goes right underneath a traffic sign or a bridge base, for example. If you've got a fully 3D environment, you can very quickly interrogate and get everything set out. Then that will actually become the model that you send to site for building. I can see it all in three dimensions.

CL: Is it important to start building intelligence into 3D modelling software?

IW: Yes, because what you can do now, it's embedding intelligent data within the 3D model that provides the client with the asset data that they require. They can identify that what there looking at, for example, a 180mm water main, and that it's made out of HDPE and it was supplied by Mr X whose address is Y. It should be instantly retrievable. There's a limitless amount of information you can get in there, if the software is set up right.